propagator_rk4.F90

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!! Copyright (C) 2023 Sebastian Ohlmann
!!
!! This program is free software; you can redistribute it and/or modify
!! it under the terms of the GNU General Public License as published by
!! the Free Software Foundation; either version 2, or (at your option)
!! any later version.
!!
!! This program is distributed in the hope that it will be useful,
!! but WITHOUT ANY WARRANTY; without even the implied warranty of
!! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
!! GNU General Public License for more details.
!!
!! You should have received a copy of the GNU General Public License
!! along with this program; if not, write to the Free Software
!! Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
!! 02110-1301, USA.
!!
 
#include "global.h"
 
module propagator_rk4_oct_m
  use algorithm_oct_m
  use debug_oct_m
  use global_oct_m
  use propagator_oct_m
 
  implicit none
 
  private
  public ::                            &
    propagator_rk4_t
 
  type, extends(propagator_t) :: propagator_rk4_t
    private
  end type propagator_rk4_t
 
  interface propagator_rk4_t
    procedure propagator_rk4_constructor
  end interface propagator_rk4_t
 
  !# doc_start rk4_propagation_operations
  ! Specific exponential mid-point propagation operations identifiers
  character(len=ALGO_LABEL_LEN), public, parameter :: &
    RK4_START        = 'RK4_START',             &
    rk4_finish       = 'RK4_FINISH',            &
    rk4_extrapolate  = 'RK4_EXTRAPOLATE',      &
    rk4_propagate    = 'RK4_PROPAGATE'
 
  ! Specific exponential mid-point propagation operations
  type(algorithmic_operation_t), public, parameter :: &
    OP_RK4_START        = algorithmic_operation_t(rk4_start,        'Starting RK4'),  &
    op_rk4_finish       = algorithmic_operation_t(rk4_finish,       'Finishing RK4'), &
    op_rk4_extrapolate  = algorithmic_operation_t(rk4_extrapolate,  'Extrapolate to dt/2 and dt for RK4'), &
    op_rk4_propagate    = algorithmic_operation_t(rk4_propagate,    'Propagation step for RK4')
  !# doc_end
 
contains
 
  ! ---------------------------------------------------------
  function propagator_rk4_constructor(dt) result(this)
    float,                  intent(in) :: dt
    type(propagator_rk4_t), pointer   :: this
 
    push_sub(propagator_rk4_constructor)
 
    allocate(this)
 
    this%predictor_corrector = .false.
    this%start_operation = op_rk4_start
    this%final_operation = op_rk4_finish
 
    call this%add_operation(op_rk4_extrapolate)
    call this%add_operation(op_rk4_propagate)
    call this%add_operation(op_update_couplings)
    call this%add_operation(op_update_interactions)
    call this%add_operation(op_iteration_done)
    call this%add_operation(op_rewind_algorithm)
 
    this%algo_steps = 1
    this%dt = dt
 
    pop_sub(propagator_rk4_constructor)
  end function propagator_rk4_constructor
 
end module propagator_rk4_oct_m
 
 
!! Local Variables:
!! mode: f90
!! coding: utf-8
!! End: